用Java来获取访问者真实的IP地址

               

主要说明

在JSP里，获取客户端的IP地址的方法是：request.getRemoteAddr()，这种方法在大部分情况下都是有效的。但是在通过了Apache,Squid等反向代理软件就不能获取到客户端的真实IP地址了。如果使用了反向代理软件，用request.getRemoteAddr()方法获取的IP地址是：127.0.0.1或192.168.1.110，而并不是客户端的真实ＩＰ。

　　经过代理以后，由于在客户端和服务之间增加了中间层，因此服务器无法直接拿到客户端的 IP，服务器端应用也无法直接通过转发请求的地址返回给客户端。但是在转发请求的HTTP头信息中，增加了X－FORWARDED－FOR信息。用以跟踪原有的客户端IP地址和原来客户端请求的服务器地址。当我们访问index.jsp/时，其实并不是我们浏览器真正访问到了服务器上的index.jsp文件，而是先由代理服务器去访问index.jsp ，代理服务器再将访问到的结果返回给我们的浏览器，因为是代理服务器去访问index.jsp的，所以index.jsp中通过request.getRemoteAddr()的方法获取的IP实际上是代理服务器的地址，并不是客户端的IP地址。

（一）方法一　

　于是可得出获得客户端真实IP地址的方法一：

public String getRemortIP(HttpServletRequest request) {  
    if (request.getHeader("x-forwarded-for") == null) {  
        return request.getRemoteAddr();  
    }  
    return request.getHeader("x-forwarded-for");  

}  

（二）方法二

　　获得客户端真实IP地址的方法二：
public String getIpAddr(HttpServletRequest request) {  
    String ip = request.getHeader("x-forwarded-for");  
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
        ip = request.getHeader("Proxy-Client-IP");  
    }  
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
        ip = request.getHeader("WL-Proxy-Client-IP");  
    }  
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
        ip = request.getRemoteAddr();  
    }  
    return ip;  
}  

　　可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？

　　答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。如：
X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100

用户真实IP为： 192.168.1.110

（三）方法三，参考网友代码

import javax.servlet.http.HttpServletRequest;    /**  * 自定义访问对象工具类  *   * 获取对象的IP地址等信息  * @author X-rapido  *  */  public class CusAccessObjectUtil {        /**      * 获取用户真实IP地址，不使用request.getRemoteAddr();的原因是有可能用户使用了代理软件方式避免真实IP地址, *       * 可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？      * 答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。      *       * 如：X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130,      * 192.168.1.100      *       * 用户真实IP为： 192.168.1.110      *       * @param request      * @return      */      public static String getIpAddress(HttpServletRequest request) {          String ip = request.getHeader("x-forwarded-for");          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("Proxy-Client-IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("WL-Proxy-Client-IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_CLIENT_IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_X_FORWARDED_FOR");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getRemoteAddr();          }          return ip;      }        }

 /**

 *获取端口

 */

public void doGet(HttpServletRequest request, HttpServletResponse response)    throws ServletException, IOException {   String uri = request.getRequestURI();//返回请求行中的资源名称   String url = request.getRequestURL().toString();//获得客户端发送请求的完整url   String ip = request.getRemoteAddr();//返回发出请求的IP地址   String params = request.getQueryString();//返回请求行中的参数部分   String host=request.getRemoteHost();//返回发出请求的客户机的主机名   int port =request.getRemotePort();//返回发出请求的客户机的端口号。   System.out.println(ip);   System.out.println(url);   System.out.println(uri);   System.out.println(params);   System.out.println(host);   System.out.println(port);}

（四）网友总结的几种方法:

/**     * 获取客户端ip地址(可以穿透代理)     *      * @param request     * @return     */    public static String getRemoteAddr(HttpServletRequest request) {        String ip = request.getHeader("X-Forwarded-For");        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            ip = request.getHeader("Proxy-Client-IP");        }        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            ip = request.getHeader("WL-Proxy-Client-IP");        }        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            ip = request.getHeader("HTTP_CLIENT_IP");        }        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            ip = request.getHeader("HTTP_X_FORWARDED_FOR");        }        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            ip = request.getRemoteAddr();        }        return ip;    }    private static final String[] HEADERS_TO_TRY = {         "X-Forwarded-For",        "Proxy-Client-IP",        "WL-Proxy-Client-IP",        "HTTP_X_FORWARDED_FOR",        "HTTP_X_FORWARDED",        "HTTP_X_CLUSTER_CLIENT_IP",        "HTTP_CLIENT_IP",        "HTTP_FORWARDED_FOR",        "HTTP_FORWARDED",        "HTTP_VIA",        "REMOTE_ADDR",        "X-Real-IP"};    /***     * 获取客户端ip地址(可以穿透代理)     * @param request     * @return     */    public static String getClientIpAddress(HttpServletRequest request) {        for (String header : HEADERS_TO_TRY) {            String ip = request.getHeader(header);            if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {                return ip;            }        }        return request.getRemoteAddr();    }    /***     * 获取客户端ip地址(可以穿透代理)     * @param request     * @return     */    public static String getClientIpAddr(HttpServletRequest request) {          String ip = request.getHeader("X-Forwarded-For");          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("Proxy-Client-IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("WL-Proxy-Client-IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_X_FORWARDED_FOR");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_X_FORWARDED");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_X_CLUSTER_CLIENT_IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_CLIENT_IP");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_FORWARDED_FOR");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_FORWARDED");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("HTTP_VIA");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getHeader("REMOTE_ADDR");          }          if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {              ip = request.getRemoteAddr();          }          return ip;      }    public static String getIpAddr(HttpServletRequest request) {        String ip = request.getHeader("X-Real-IP");        if (null != ip && !"".equals(ip.trim())                && !"unknown".equalsIgnoreCase(ip)) {            return ip;        }        ip = request.getHeader("X-Forwarded-For");        if (null != ip && !"".equals(ip.trim())                && !"unknown".equalsIgnoreCase(ip)) {            // get first ip from proxy ip            int index = ip.indexOf(',');            if (index != -1) {                return ip.substring(0, index);            } else {                return ip;            }        }        return request.getRemoteAddr();    }

我使用的是spring MVC框架,测试的控制器代码如下:

package com.web.controller;import java.util.HashMap;import java.util.Map;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import com.common.util.SystemHWUtil;import com.common.util.WebServletUtil;import com.string.widget.util.ValueWidget;import com.util.JSONPUtil;/*** * 用于测试跨域 * @author huangweii * 2015年5月29日 */@Controller@RequestMapping("/cors")public class CORSController {    @ResponseBody    @RequestMapping(value = "/simple",produces=SystemHWUtil.RESPONSE_CONTENTTYPE_JSON_UTF)    public String corsJsonSimple(HttpServletRequest request,String callback){        String content;        Map map=new HashMap();        map.put("username", "黄威");        map.put("age", "27");        map.put("address", "beijing");        content=HWJacksonUtils.getJsonP(map, callback);        System.out.println("getIpAddr:"+WebServletUtil.getIpAddr(request));        System.out.println("getRemoteAddr:"+WebServletUtil.getRemoteAddr(request));        System.out.println("getClientIpAddr:"+WebServletUtil.getClientIpAddr(request));        System.out.println("getClientIpAddress:"+WebServletUtil.getClientIpAddress(request));        return content;    }}